Abstract

The aim of this study was to investigate the frequency of CTX-M type extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains which have become emerging etiologic agents of urinary tract infections (UTIs). A total of 310 E. coli isolates recovered from UTIs were screened for ESBL production by VITEK2 system and the double-disk synergy tests. In addition, ESBL positive isolates were selected for typing of bla_CTX-Mgenes by PCR screening followed by DNA sequencing analysis permitting the differentiation of the CTX-M subtypes. A pulsed-field gel electrophoresis (PFGE) assay was also performed to check for a possible clonal relation among these isolates. ESBL positivity was detected in 77 (24.8%) of isolates. Subsequently, 46 (14.8%) of ESBL positive E. coli isolates were shown to be carrying bla_CTX-M genes of which 30 (9.6%) were found to be CTX-M-15 producers, while the remaining 16 (5.1%) were CTX-M-14 producers. No major clonal relationship among these bla_CTX-M producers was found. Wedemonstrated the presence of CTX-M-14 producer E. coli strains for the first time in Turkey and provided epidemiologic data suggesting the evidence for the ongoing dissemination of CTX-M type ESBLs.

Key words: CTX-M-14, extended-spectrum beta-lactamase (ESBL), Escherichia coli, pulsed-field gel electrophoresis (PFGE)